Broadcast Channel (BCH) data in wideband code division multiple access (WCDMA) systems is transmitted in 20 milli-second (ms) segments, whereas each radio frame of a WCDMA system is 10 ms long. Since BCH data must therefore be transmitted in two WCDMA radio frames, the chances of getting the correct frame alignment during decoding is 50%.
Failure of decoded data to satisfy the parity check may indicate incorrect frame alignment. Existing BCH decoding schemes for WCDMA systems typically assume that a decoding error may have resulted from signal distortion during transmission (e.g., multi-path interference), either in lieu of or in addition to incorrect frame alignment. Such systems generally discard the received data and restart with a frame, based on timing, which should provide correct frame alignment if incorrect alignment was at least partially responsible for the initial decoding failure. However, this may require as many as nine frames before decoding may be successfully undertaken on received frames.
There is, therefore, a need in the art for improved BCH decoding providing faster recovery from incorrect initial frame alignment.